Sudden changes in the volume of meltwater contribute more to the acceleration – and eventual loss – of the Greenland ice sheet than the gradual increase of temperature, according to a University of British Columbia study.

The ice sheet consists of layers of compressed snow and covers roughly 80 per cent of the surface of Greenland. Since the 1990s, it has been documented to be losing approximately 100 billion tonnes of ice per year – a process that most scientists agree is accelerating, but has been poorly understood. Some of the loss has been attributed to accelerated glacier flow towards ocean outlets.

Now a new study, to be published tomorrow in the journal Nature, shows that a steady meltwater supply from gradual warming may in fact slow down glacier flow, while sudden water input could cause glaciers to speed up and spread, resulting in increased melt.

“The conventional view has been that meltwater permeates the ice from the surface and pools under the base of the ice sheet,” says Christian Schoof, an assistant professor at UBC’s Department of Earth and Ocean Sciences and the study’s author. “This water then serves as a lubricant between the glacier and the earth underneath it, allowing the glacier to shift to lower, warmer altitudes where more melt would occur.”

Noting observations that during heavy rainfall, higher water pressure is required to force drainage along the base of the ice, Schoof created computer models that account for the complex fluid dynamics occurring at the interface of glacier and bedrock. He found that a steady supply of meltwater is well accommodated and drained through water channels that form under the glacier.

“Sudden water input caused by short term extremes – such as massive rain storms or the draining of a surface lake – however, cannot easily be accommodated by existing channels. This allows it to pool and lubricate the bottom of the glaciers and accelerate ice loss,” says Schoof, who holds a Canada Research Chair in Global Process Modeling.

“This certainly doesn’t mitigate the issue of global warming, but it does mean that we need to expand our understanding of what’s behind the massive ice loss we’re worried about,” says Schoof.

A steady increase of temperature and short-term extreme weather conditions have both been attributed to global climate change. According to the European Environment Agency, ice loss from the Greenland ice sheet has contributed to global sea-level rise at 0.14 to 0.28 millimetres per year between 1993 and 2003.

“This study provides an elegant solution to one of the two key ice sheet instability problems identified by the Intergovernmental Panel on Climate Change in their 2007 assessment report,” says Prof. Andrew Shepherd, an expert on using satellites to study physical processes of Earth’s climate, based at the University of Leeds, the U.K.

“It turns out that, contrary to popular belief, Greenland ice sheet flow might not be accelerated by increased melting after all,” says Shepherd, who was not involved in the research or peer review of the paper.

The research was supported by the Canada Research Chairs Program, the Natural Sciences and Engineering Research Council of Canada, and the Canadian Foundation for Climate and Atmospheric Sciences through the Polar Climate Stability Network.

“but has been poorly understood……….”
“Schoof created computer models………”
=============================================
and all this time I was under the impression that you had to understand
something in order to create a computer game………..

Putin Suggests Germany Replaces Nuclear with Firewood
Russian prime minister Vladimir Putin has told German businessmen that they may have to rely on Russian firewood for heating if they do not want to construct new nuclear power plants or bring in Russian gas supplies. At a business conference organized in Berlin by the German newspaper Sueddeutsche Zeitung, Putin recognised that “the German public does not like the nuclear power industry for some reason.” He continued: “But I cannot understand what fuel you will take for heating. You do not want gas, you do not develop the nuclear power industry, so you will heat with firewood?” Putin then noted, “You will have to go to Siberia to buy the firewood there,” as Europeans “do not even have firewood.”
World Nuclear News
1 Dec 2010http://www.world-nuclear-news.org/newsarticle.aspx?id=28907

It’s worse than we could ever think, that is, nothing is happening due to global warming after all, except the big freeze. No wonder more and more scientists are coming out of the woodworks and declare openly their skepticsm on AGW or, as it is called now: CFDtGW(Catastrophic Freezing Due to Global Warming)

There is too much use of the term ” accelerate” when the trend line is linear. Acceleration implies a constant increase in velocity e.g. an object will accelerate (assuming zero air resistance) under gravity and implies a constant force applied to a frictionless object.
A moving glacier is not moving friction free.
They are not trying to frighten people are they ?

From the article “According to the European Environment Agency, ice loss from the Greenland ice sheet has contributed to global sea-level rise at 0.14 to 0.28 millimeters per year between 1993 and 2003″…

Sometime in the future, well past my lifetime, humans will be huddled around low lattitudes and altitudes, glaciers of a new ice age encroaching upon them, yet there’ll still be a paper released by a some wag that says “Snowball Earth maybe caused by solar and planetary perturbations, but this certainly doesn’t mitigate the issue of global warming.”

When will they stop? When will they realise the damage they are doing to science? When will they care?

Its encouraging to see more thought and testing of alternative theories AND using computer models to explore, test and check. That’s advancement of scientific knowledge and will no doubt spur others on to further and better understanding of the issues that were grabbed and used as (incorrect) headlines.

Interesting the paper seems to have been embraced by Nature, the journal that seemingly worked with the team to stifle alternative theory to the all conquering CAGW meme.

I do love the spin though, and the “contrary to belief” replacing” our “solid scientific consensus” tales of old CAGW. Change for the good of science? or is this new confession “we got it slightly wrong” , a case of the Fabian wolf disguising itself as just a sheep, to sell another agenda?

“The ice sheet consists of layers of compressed snow and covers roughly 80 per cent of the surface of Greenland. Since the 1990s, it has been documented to be losing approximately 100 billion tonnes of ice per year – a process that most scientists agree is accelerating, but has been poorly understood.”

So, a gigatonne is 1 billion metric tonnes, and 100 gigatonnes = 100 billion tonnes. A gigatonne of ice weighs about 9% less than a gigatonne of water, so lets use water, as it gives us a nice fudge factor. Now a metric ton of water has a volume of 1 cubic metre, so a gigatonne of water has a volume of 1 cubic kilometre.

And 100 gigatonnes = 100 cubic kilometres.

Greenland has, I believe, an estimated 2.6 million cubic kilometres of ice?

And I’m supposed to be worried about it losing 100 cubic kilometres a year for the last 20 years? That would be 2000 cubic kilometres, or less than .0008 of it’s estimated volume, over the last 20 years?

At what point does that disappear into the error range of the estimates themselves?

In other words we don’t known why its happening and this is one idea for a cause .
Which is actual fair enough , and certainly makes a change from ‘we know for a fact its down to AGW’ when that is not the case. But its underlines again the point that there are quite a few of issues were the sceince is far from settled , which is what the secptics have been saying all along.

Putins got Merkel by the short and curlys.
His blunt sarcasm is refreshing. Though funny to read, it’s sad for the Germans, on hands and knees at the feet of the Russians, (yet again).
Well, they will form government with greenies won’t they. Reap sow and all that.

Thnx Ted, being a political piece, I passed it onto Andrew Bolt (link at side bar) with due citation to you.

I think that the AGWs will explain it this way–Global warming will cause more rain water in the Greenland area increasing the liquid water that causes glacier melt to accelerate and a large increase in the rate of sea level rise across the globe. The U.S. must increase it’s payments to the U.N. so they can stop this horrible problem before we all perish. All U. S. citizens should also sign up to stop any increase in “die hydrogen monoxide” increase which is another terrible problem.

Sometime in the future, well past my lifetime, humans will be huddled around low lattitudes and altitudes, glaciers of a new ice age encroaching upon them, yet there’ll still be a paper released by a some wag that says “Snowball Earth maybe caused by solar and planetary perturbations, but this certainly doesn’t mitigate the issue of global warming.”

When will they stop? When will they realise the damage they are doing to science? When will they care?

They’ve already covered that very eventuality – should it occur, clearly we’ve just passed some ‘tipping point’ or another with all the CO2 we released. Sigh.

Inevitably still some spin but at least there is recognition that something other than global warming can drive nature.

Meanwhile in the UK, lets hope it is just weather and not climate that we are presently experiencing since if the recent trend (now 3 cold winters in a row) continues, the UK will not be a pleasant place to live. Now, if only the Government could divert some of the money it is wasting on windmills to sorting out the infrastructure so that the UK does not grind to a halt when it keeps on experiencing a 1 in 30 years or 1 in 100 cold snap we would not be forced to call in the army to dig us out.http://www.dailymail.co.uk/news/article-1336705/UK-big-freeze-Army-standby-coldest-December-100-years.html

UBC is one of the “big boy” Universities in Canada, I hope to go there and finish my Chemistry and Physics degrees for a career in Nuclear Industry and and related good stuff (like space travel).
This is an academic “earthquake” in Canada.

Guess who the cave dwellers facing the rock fall are?

If you guessed the “ass”orted mixed fruit and nuts that make up the AGW crowd then you are correct.

I try not to laugh at most people who have NO idea about global weather or global temperatures (or the history of either).

The recent publications supporting global warming always seem to show the “ice-hockey stick” graph extending back about 1500 years. The graph shows an extreme rise in temperature over the past 100 years or so. I don’t deny any large rise, but I like to add some scientific data…

1. The Earth is coming out of “the little ice-age;” and
2. There are other graphs showing temperatures over longer periods of time.

The PALEOMAP project has a great graph showing average global temperatures (estimates, of course) over 2 billion years. If I was to base my argument on a graph, I would look at the graph presented and say we were just getting back to normal temperatures…

Most people are trying to SPIN facts to fit their “political” or “social” objectives rather than look at facts and outcomes. Man does affect the environment (as do other living things and chemicals). Limiting our impacts isn’t a bad thing, and I do like the islands in the Pacific and the land-mass of Florida. If I can limit my impacts to keep water lower in those areas I will. I also like skiing (in California and elsewhere), so I will do what I can to keep snow in the lower 48.

However, most people do need to get lots of education re: global temperatures and many other topics…

Is there a direct measurement temperature record for Greenland? How many sites over how long?

The Article mentions global warming and Greenland and ice loss in the same article, but does not document how much warming there has been in Greenland (esp in last 15 years, what with this accelerating problem of melting).

The ice sheet consists of layers of compressed snow and covers roughly 80 per cent of the surface of Greenland. Since the 1990s, it has been documented to be losing approximately 100 billion tonnes of ice per year – a process that most scientists agree is accelerating, but has been poorly understood. Some of the loss has been attributed to accelerated glacier flow towards ocean outlets.

Is that 100 billion tonnes per year the NET loss; or is it just how much melts or falls off each year.
so how much does it gain every year ?

The (at least) 100 Gigatonnes is net loss – it is not from a model or anything, it comes from direct measurement of the mass using a pair of satellites which detect the variation in the gravitational potential. (and the authors of the article have been careful to quote the lower end of the range for the mass loss)

I’d just like to say that I don’t have a problem with computer models. Yes, I know, many of you are going to have a conniption at this, please, bear with me.

Models do, despite all their bad press, provide us with very good insight into how things might work in the real world.

Everything is simulated these days, chemical interactions for drug discovery, physical properties of new aircraft designs, F1 car materials, manufacturing processes, everything. The difference is that all these things are simulated then tested in the real world to see if the sims stack up.

It seems that its only climate research (and financial services perhaps) where models are taken as gospel and used as evidence and fact without any physical measurements to back them up. With something as complex and chaotic as climate, the chances of the model being correct in the first few iterations (which is where we are at the moment) is very small, as indeed is now becoming blatantly obvious – take Dr Curry’s recent posts at her blog for example – climate models are incomplete and the results should be used in that context.

With the glacier situation, its a relatively well bounded problem that fluid dynamics type models can actually get close to simulating, or at least accurately enough to form a testable theory. From what I understand (I’m sure there are many here who use Fluent, CFX or other CFD apps in their day jobs who can explain better than I), the main challenges with modelling this kind of thing are how you define the boundary layer between liquid and solid and not the physical properties of the materials. I guess all that’s needed now is some empirical measurements to see how well the model stacks up.

Forget the yearly stuff. Statistically 2010 was normal. Only 3 years since 1958 were outside of 2 sigma for SMB change. Two of those years were positive. Overall change in accumulation is trivial for any of the studies that are 50+ years.

I agree with Charlie, there are many situations where computer modelling is very useful. But only when the model can be tested against observations. And even then, only when the number of unknown parameters in the model is reasonably small (unlike climate modelling where the number of unknown parameters is huge). Also, it needs to be appreciated that the output of the model is not “data” and that if the model doesn’t agree with the observations, you don’t change the observations (I know, I know, but this is climate science).

mitchel44 says:
December 8, 2010 at 4:27 pm
“…
So, a gigatonne is 1 billion metric tonnes, and 100 gigatonnes = 100 billion tonnes. A gigatonne of ice weighs about 9% less than a gigatonne of water, so lets use water, as it gives us a nice fudge factor. Now a metric ton of water has a volume of 1 cubic metre, so a gigatonne of water has a volume of 1 cubic kilometre.
…”

You lose me with the bolded statement above. Wouldn’t a gigatonne of each weigh a gigatonne? Of course the density and volume could/would be different but that’s another matter.

I’m trying to understand the process so please stop me if I have it wrong:

* Observe an event
* Nature is too complex to understand, so build a model
* Design model to replicate observed but not well understood phenomena – accept rounding errors and playing dice as God does as unavoidable necessity – confidence level remains high, hell why should it not.
* Use model rather than observations to understand natural phenomena. Confidence level surges as results validate prediction to 3 decimal places.
* Write up a paper that actually says the above or worse and use peer review speak so peer pals won’t be put off by injecting language of commoners into the puddin’.
* Wait for Nobel prize in science fiction

I wonder how much ice was on greenland just before the LIA set in? Does anyone know of a sea level peak at this time?

BAA:
When will they stop? When will they realise the damage they are doing to science? When will they care?

Never soon. Those people got the legal right to call themselves “scientists” by means of political decisions including laws set up to “produce” more people working in the area of science. This can’t and didn’t work. What was produced is a horde of numbs hindering the Really Qualified to perform their duty.
IMO this leads to the relatively desinterest[sp?] by the RQ to fight against the flood of nonsense. They know they can’t win.
OTOH the “other” party knows that they can’t compete with RQ. They hate this fact and react like naughty children but politically correct which helps the politicans responsible for the “production” laws to claim those laws to be successful.
Nice dilemma.

Funny, I believe it was Germany based E-on energy corporation that got a contract to build 5000 MW worth of nuclear power plant in England. But Germany is dependent on gas, or now firewood, from Russia. That’s hilarious. :-()

But isn’t weather controlled by global climate change? So Mann-made global warming changes the climate which changes the weather. So we still need to ruin everyones economy and go back to 18th century agrarian style of living.
/sarc off

I note the droll comments and the insight that “this new study” is a computer model, not empirical.

I also note NASA claims to know by some secret method of altimetry and gravity sensors in space how much ice is melting away from Greenland, and that almost all studies of glacier movement in Greenland are focused on melting rather than growing glaciers as a function of available academic funding.

I would like to note that while Europe does have a little bit of firewood left, Greenland has none. Therefore I would like to ask Prime Minister Putin to worry a little more about the Greenlanders and a little less about the Germans, who in a pinch have been known to find all manner of things to use as fuel.

“does not mitigate the global warming” — the obligatory statement to stay in the good graces of the CAWG camp.

“loss of ice that worries us” — we should be emotionally detached from the subject of scientific study. Science seeks truth. Not emotion. Leave your emotional baggage at the lab door, please, professor.

I’m curious–is it even possible to measure 0.14 or 0.28 mm per year sea level rise? Does whatever measurement there is get lost in the error range? Please explain to me, someone, how this actual measurement can be accomplished?

Is there a direct measurement temperature record for Greenland? How many sites over how long?

The Article mentions global warming and Greenland and ice loss in the same article, but does not document how much warming there has been in Greenland (esp in last 15 years, what with this accelerating problem of melting).

The (summer) temperatures 1930-1950 were even somewhat higher than current and melting was at least as strong as today… So, no “global” warming but a regional cycle of warmer and cooler periods, probably related to the NAO…

Meanwhile of course, Greenland is experiencing record high temps (and has been for over a year) under extraordinary high pressure system, the same of which are sending cold polar air south over Europe and the eastern U.S.

maestrlom the magnificient says:
good dig
Colin from Mission B.C. says: blah blah
did I miss the tone of the paper?
I thought they are saying “agw” has nothing to do Greenland glaciers calving.
it’s just weather, not climate.
I think you took the wrong courses, dude

Meanwhile, over at www dot spaceweather dot com, the historically long and deep Solar Minimum continues.
I too was wondering just how much ice was on Greenland before the Little Ice Age set in. Some of us would like to think that that is what’s “normal” for Earth. It was a very beneficial time for all life on Earth, including the Vikings who had a thriving agricultural colony on Greenland. Of course the “scientists” at the CRU had to make that period of Earth’s history disappear, it was an inconvenient truth that could not be let out. The planet would have to warm up at least 8º to get back to where it was in 1300 AD.
I have asked many AGW alarmists on forums, just what is Earth’s NORMAL temperature? I ask again. Cue the crickets.